Ball-grinding machine.



B. EITNER.

BALL GRINDING MACHINE.

APPLICATION FILED DEC. 31, 1910.

1,036,590, Patented Aug. 27, 1912.

4 SHEETS-SHEET 1.

I/VVE/VTOR:

WITNESSES:

COLUMBIA FLANDGRAPH co., WMHINOTON, n. c.-

B. EITNER.

BALL GRINDING MACHINE.

APPLIGATION FILED DEC. 31, 1910.

Patented Aug. 27, 1912.

4 SHEETS-SHEET 2.

VV/T/VESSES B. EITNER.

BALL GRINDING MACHINE.

APPLICATION FILED D110. 31, 1910.

1,036,590,; Patented Aug. 27, 1912.

4 SHEETS-SHEET 3,

Q EJ AZWWJ) COLUMBIA PLANQGRAPH cm. wAsmNumN, 0. cl

B. EITHER.

BALL GRINDING MACHINE.

APPLICATION FILED DEC. 31, 1910.

4 SHEETS-SHEET 4.

IN VE/V 70 My 446507716);

P atented Aug. 27, 1912.

WITNESSES! @w O FD COLUMBIA PMNOGRAPK c TINITE S IBERTHOLD EITNER, OFBERLIN, GERMANY, ASSIGNOR TO DEUTSCHE WAFFEN- UND MUNITIONSFABRIKEN, OFBERLIN, GERMANY.

BALL-GRINDING MACHINE.

To all whom it may concern:

Be it known that I, BERTHOLD EITCNER, workmaster, a subject of the Kingof Prus sia, residing at No. 1a Gotzkowskystrasse, Berlin, in theKingdom of Prussia, Germany, have invented certain new and usefulImprovements in and Relating to Ball- Grinding Machines, of which thefollowing is a full, clear, and exact description.

As is known in ball-grinding machines in order to obtain circular ballsof uniform size the balls must be subjected to a frequent and thoroughmixing during the grinding process. For this purpose each individualball is constantly caused to change its axis of rotation, its positionbetween the other balls and also its grinding channel, in such a mannerthat as far as possible all the balls assume another position and orderin another grinding channel after each circuit. Heretofore, especiallyin the case of ball grinding machines the grinding plates of which areformed with concentric annular channels, mixing of the balls has beeneffected owing to the fact that the balls running in the grindingchannels were conveyed out of the grinding channels into a recess in oneof the grinding plates, conducted into special mixing devices and thenafter being mixed returned by special conveyer members into the grindingchannels of the grinding plates, it being necessary to impart to theballs situated outside the grinding plates an acceleration correspondingto the speed of the grinding plates in order to prevent them from beingretarded relatively to the grinding plates, that is to say, in order toobtain a uniform driving or movement by the ro tating grinding plates ofthe balls which are returned and thus insure the complete replenishmentof the grinding channels that have previously been emptied.

The present invention relates to a ball grinding machine in which themixing of the balls is regulated exactly in accordance with the speed ofthe grinding plates for the time being, in such a manner that theemployment of special conveyer members and also the necessity for actingupon the balls or their conveyer members for producing an accelerationof the balls when they are re-introduced is rendered unnecessary.

In accordance with the invention the balls are discharged from thegrinding channels, mixed, and returned to the grinding chan-Specification of Letters Patent.

Application filed December 31, 1910.

Patented A11 27, 1912.

Serial No. 600,290.

nels, inside the recess in the grinding plates and automatically by thedriving force of the rotating plates so that the displacement of theballs is produced in constant agreement with the speed of the grindingplates, without the assistance of conveyer or acceleration members. Thisimprovement also renders it possible for the balls running in thegrinding channels to remain constantly in contact with the grindingmedium supplied continuously at an appropriate place (to the ball mixingchamber for example) during the whole of the grinding operation that isto say during the mixing which takes place in the machine itself. Thisarrangement presents the advantage that the so-called drumming of theballs, that is to say, the subsequent treatment of the ground balls indrums filled with grinding material is rendered unnecessary, therebygreatly simplifying and shortening the en tire process of manufacturingthe balls.

Two embodiments of the invention are illustrated by way of example inthe accompanying drawings in which:

Figure l is an elevation of the ball grinding machine. Fig. 2 is asectional plan on the line 22 in Fig. 1. Fig. 3 is a vertical sectionthrough the upper part of a machine with rotary lower grinding plate.Fig. 4: is a corresponding section of a machine with rotating uppergrinding plate. Figs. 5 and 6 illustrate the ball mixing deviceseparately to a larger scale, Fig. 5 being a longitudinal section andFig. 6 a plan in section on the line 66 of Fig. 5.

Both the grinding plates are formed with concentric annular channels andthe upper plate a is removable from the lower plate I) in a verticaldirection. During operation the plates are pressed one against the otherby adjustable spring pressure.

A guide member 0 is arranged in a recess in the upper plate a andcomprises passages d leading obliquely upward; these passages connectbelow with the annular grooves in the grinding plates and open abovestaggered relatively to these annular grooves into the chamber 6 whichbehind the guide members 0 remains free in the recess in the platesabove the channels of the plate I). A circulation path 9 connects withthe innermost passages d of the guide member and,

leads to the outermost passages. The chamher 6 is preferably sub-dividedinto separate chambers below by means of partitions f which fit againstthe walls of the channels in the plate Z). As the channels increase insize from the interior toward the exterior, the channels situated towardthe exterior contain more than the inner channels. In order to insureuniform charging of all the channels, the partitions decrease step bystep in height toward the exterior.

The apparatus operates in the following manner: Nov matter whether thelower or the upper plate rotates the balls running into the channels ofthe lower and upper plates are raised out of the channels after eachrevolution by the guide member 0 through the passages (Z of which theyare conducted obliquely upward until under the pressure of the followingballs they fall out of these passages through the chamber 6 into thechannels of the lower plate by which they are carried along. Owing tothe inclination of the passages (Z to the channels the balls aredeflected in such a manner that when they again come between thegrinding plates they enter different chan nels. In addition to this inthe chamber 6 they fall over and through each other so that theirrelative position, their axis of rotation and their order are changed.The balls therefore receive the movements required for their change ofposition exclu sively by the driving force of the rotating grindingplates. The intensity of these movements therefore always correspondswith the speed of the grinding plates so that no adjustment of theapparatus in correspondence with the speed of the grinding disks isnecessary. Special conveyer and ac celerating means are likewiseunnecessary as the balls fall directly at the feed place. The apparatusis much smaller and simpler and more certain in its operation than priorapparatus because of the omission of all conveyer mechanism whichincreases the risk of interruption of the operation.

In the machine in which the lower plate is rotary (Figs. 3 and 5) thedevice for feed ing and mixing the grinding medium consists broadly ofthe reservoir n provided with a hopper-shaped sieve bottom, the annularreservoir 0 which tapers downward and which fits the upper part of thereservoir a while leaving a narrow annular interval at its lower part,and of the discharge hopper h which projects directly into the ballmixing chamber 6. The reservoir 12 is filled with the grinding mediumsuch as emery powder for example, while the second reservoir 0surrounding the upper part of the reservoir 'n, serves for the receptionof the liquid (oil, petroleum or the like) which is supplied to thisreservoir through the pipe m. The liquid contained in this reservoirflows through the open space at the bottom trickles over the sieve-likebottom of the reservoir n and thus washes the grinding powder out of themeshes of the sieve. The grinding mass thus formed falls into thedischarge hopper h and finally passes through it into the ball mixingchamber c, that is to say between the grinding plates.

In the constructional form of the machine illustrated in Fig. 4 with arotating upper plate the device for mixing and supplying the grindingmedium consists of a plate t connected with the rotating upper plate andin which an annular groove u is cut; this groove runs obliquely to theplane of the plate and at its deepest part opens into the ball mixingchamber formed in the upper grinding plate a. A discharge pipe 8 isarranged above the annular groove 10 and through this pipe the liquid isconducted into the said passage. The passage a is partially filled withemery powder which is carried by the stream of liquid issuing from theoutlet 5 toward the lower opening of the passage and through this intothe ball mixing chamber 6 or between the grinding plates.

Owing to the cooperation of the two simiwith a uniformly supplied pureand fine grinding medium, the balls manufactured are exactly equal insize, perfectly round smooth and free from all grinding ridges, orincisions, so that they require no subsequent treatment whatever.

lVhat I claim as my invention and desire to secure by Letters Patent is:

1. In a machine of the character described, the combination of twogrinding plates, movable relatively to one another and one of which hasa recess therein, grinding grooves in the grinding faces of said plates,and a guide member in said recess, leaving a space at the rear thereofover the grinding grooves, adapted to lift balls out of said grindinggrooves and deliver them to said space at the rear thereof.

2.111 a machine of the character described, the combination of twogrinding plates, movable relatively to one another and one of which hasa recess therein, grinding grooves in the grinding faces of said plates,a guide member in said recess, leaving a space at the rear thereof overthe grinding grooves, adapted to lift balls out of said grinding groovesand deliver them to said space at the rear thereof, said guidememberhaving upwardly extending guide passages therein.

3. In a machine of the character described, the combination of twogrinding plates, movable relatively to one another and one of which hasarecess therein, grinding grooves in the grinding faces of said plates,and a guide-member in said recess, leaving a space at the rear thereofover the lar grinding members (cast iron plates) grinding grooves,adapted to lift balls out of said grinding grooves and deliver them tosaid space at the rear thereof, said guidemember having upwardlyobliquely extending guide passages therein and a circulation-path orrunway from a guide passage to a grinding groove.

4. In a machine of the character described, the combination of twogrinding plates, movable relatively to one another and one of which hasa recess therein, grinding grooves in the grinding faces of said plates,and a guide member in said recess, leaving a space at the rear thereofover the grinding grooves, adapted to lift balls out of said grindinggrooves and deliver them to said space at the rear thereof, saidguidemember having partitions extending across said space in the rear ofsaid member and corresponding with said grinding grooves in the lowerplate.

5. In a machine of the character described, the combination of twogrinding plates, movable relatively to one another and one of which hasa recess therein, grinding grooves in the grinding faces of said platesand a guide-member in said recess, leaving a space at the rear thereofover the grinding grooves, adapted to lift balls out of said grindinggrooves and deliver them to said space at the rear thereof, saidguidemember having partitions extending across said space in the rear ofsaid member and corresponding with said grinding grooves in the lowerplate, the height of said partitions decreasing from one side of theseries to the other, whereby balls may be distributed from onepartitioned space to another.

6. In a machine of the character described, the combination of twogrinding plates, movable relatively to one another and one of which hasa recess therein, grinding grooves in the grinding faces of said plates,and a guide-member in said recess, leaving a space at the rear thereofover the grinding grooves, adapted to lift balls out of said grindinggrooves and deliver them to said space at the rear thereof, and meansfor supplyii'ig a grinding medium adapted to discharge 1n sald space.

7. In a machine of the character described, the combination of twogrinding plates, movable relatively to one another and one of which hasa recess therein, grinding grooves in the grinding faces of said plates,and a guide in said recess, leaving a space at the rear thereof over thegrinding grooves, adapted to lift balls out of said grinding grooves anddeliver them to said space at the rear thereof and means for supplying agrinding medium adapted to discharge in said space, said meanscomprising a hoppershaped sieve for containing a grinding mediumsurrounded by a liquid reservoir from which liquid trickles onto saidsieve.

In witness whereof, I have hereunto signed my name in the presence oftwo subscribing witnesses.

BERTHOLD EITNER.

Witnesses:

ROBERT MIOHELsKY, HENRY HAsPER.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, I). 0.

